What is the main function of the intake manifold in a reciprocating engine?

What is the main function of the intake manifold in a reciprocating engine?

• A. Distribute the air-fuel mixture to the cylinders
• B. Filter incoming air
• C. Regulate exhaust flow
• D. Store fuel

Answer: (A)

The main function is to route the incoming air (or the air-fuel mixture in some older designs) from the throttle body to each cylinder, using a common plenum and individual runners so every cylinder receives roughly the same charge. This even distribution helps achieve balanced combustion and smooth engine performance across RPMs. The shape and length of the runners can tune how the air flows at different speeds, affecting power and efficiency. It’s not responsible for filtering air—that’s the air filter’s job—nor for regulating exhaust, which is handled by the exhaust system, and it doesn’t store fuel—the fuel system handles that.

The main function is to route the incoming air (or the air-fuel mixture in some older designs) from the throttle body to each cylinder, using a common plenum and individual runners so every cylinder receives roughly the same charge. This even distribution helps achieve balanced combustion and smooth engine performance across RPMs. The shape and length of the runners can tune how the air flows at different speeds, affecting power and efficiency. It’s not responsible for filtering air—that’s the air filter’s job—nor for regulating exhaust, which is handled by the exhaust system, and it doesn’t store fuel—the fuel system handles that.